Underwater well completion method



June 21, 1966 Y J. A. HAEBER ETAL 3,255,937

UNDERWATER WELL COMPLETION METHOD Filed July 30, 1959 1"! Sheets-Sheet l INVENTORS:

J. A. HAEBER L. e. OTTEMAN THEIR AGENT u 6 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD l7 Sheets-Sheet 2 Filed July 30, 1959 FIG. 2

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THEIR AGENT June 21, 1966 J-. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1'7 Sheets-Sheet 5 Filed July 30, 1959 INVENTORS J. A. HAEBER L. 4 OTTEMAN B =$LM EIR AGENT June 21, 19 J. A. HAEBER ETAL UNDERWATER WELL COMPLETION METHOD 1'? Sheets-Sheet. 4

Filed July 30, 1959 lNVENTORS J. A. HAEBER L. G. OTTEMAN 4 1* THEIR AGENT June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1''! Sheets-Sheet 5 Filed July 30, 1959 INVENTORS:

d. A HAEBER L. G. QTTEMAN Ewa 1, Q

THEIR AGENT June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1'? Sheets-Sheet 6 Filed July 30, 1959 FIG.

INVENTORS:

J. A. HAEBER L.G. OTTEMAN BY: HEIR AGENT June 21, 1966 Filed July 30, 1959 F I G J. A. HAEBER ETAL UNDERWATER WELL COMPLETION METHOD 1'? Sheets-Sheet. 7

INVENTORS J. A. HAEBER L.G OTTEMAN BY d HE|R AGENT June 21, 1966 J. A. HAEBER ETAL 3,255,937

UNDERWATER WELL COMPLETION METHOD 17 Sheets-Sheet 8 Filed July 30, 1959 HEI R AGENT June 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1? Sheets-Sheet 9 Filed July so, 1959 FIG. l3

INVENTORS J.A. HAEBER HEIR AGENT J1me 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD Filed July 30, 1959 1'7 Sheets-Sheet. 10

INVENTORS J.A. HAEBER 14s L.G. OTTEMAN BY .gmC.

THEIR AGENT June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD Filed July 30, 1959 17 Sheets-Sheet. 11

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INVENTORS:

J. A. HAEBER L. G. OTTEMAN B fiJ-Ru.

HEIR AGENT June 21, 1966 J. A. HAEBER ETAL UNDERWATER WELL COMPLETION METHOD 1'7 Sheets-Sheet 12 Filed July 30, 1959 FIG. 22

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s R o T N E V N J. A. HAEBER L. G. OTTEMAN gflm THEIR AGENT III/Ill FIG.25

June 21, 1966 J. A. HAEBER ETAL UNDERWATER WELL COMPLETION METHOD Filed July 30, 1959 1'7 Sheets-Sheet l3 E; I I I 20' |96 47 I92" 1 1 l 1 I I v If L205 T205 I i1 I FIG. 23 FIG 24 INVENTORS J.A. HAEBER FIG 2? use L. G. OTTEMAN B d-ALM THEIR AGE June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1'? Sheets-Sheet 14 Filed July 30, 1959 FIG 26 b [NVENTORS J.A. HAEBER .s. OTTEMAN BY flin THEIR AGEN FIG. 26 0 June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1? Sheets-Sheer. 15

Filed July 30, 1959 II V \\\k OIL OR GAS FORMATION FIG .30

INVENTORS J.A. HAEBER L.G. OTTEMAN BYJJ-R FIG-28 THEIR AGENT June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD Filed July 30, 1959 17 Sheets-Sheer. 16

INVENTORS J. A. HAEBER' 29 L.G. OTTEMAN HEIR AGENT June 21, 1966 J. A. HAEBER ETAL 3,256,937

UNDERWATER WELL COMPLETION METHOD 1''! Sheets-Sheet 1? Filed July 50, 1959 mmdl mm. v2

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INVENTORSI J.A. HAEBER L.G. OTTEMAN BY: A4

EIR AGENT United States Patent 3 256 937 UNDERWATER WEIZL C OMPLETION METHOD John A. Haeber and Lloyd G. Otteman, Houston, Tex.,

assignors to Shell Oil Company, a corporation of Deltaware Filed July 30, 1959, Ser. No. 830,538 6 Claims. (Cl. 166-46) This invention relates to the drilling of offshore wells and pertains more particularly to a method and apparatus for completing wells drilled in offshore waters which may be anywhere from 100 to 1,500 or more feet deep.

At present offshore wells are drilled either from stationary platforms anchored to the ocean floor, movable barges temporarily positioned on the ocean floor or from movable barges floating on the body of water on which drilling operations are being carried out. Regardless of the manner in which the wells are drilled, most wells are completed in a manner such that the outermost tubular member of the well extends upwardly from the ocean floor to above the surface of the Water where a wellhead or Christmas tree is mounted thereon for controlling the production of the well.

Wellheads extending above the surface of the water constitute a hazard to navigation of vessels in the area as well as constituting a structure which is readily attacked by the wave-action, it being well. known that the corrosive action of seawater and the air readily attack the normal steel platforms unless they are protected in a suitable manner by corrosive-resistant material.

It is therefore an object of the present invention to provide a method and apparatus for drilling and completing offshore wells in a manner such that the entire wellhead assembly is submerged to minimize corrosion of equipment.

A further object of the present invention is to provide a method for drilling and completing an oifshore well in a manner such that the wellhead is located below the surface of a body of water, for example, near the ocean floor, so that deep draft vessels can safely pass overhead, thus eliminating the blow-out hazard presented by the possibility of ships hitting the wellhead or a supporting platform therefor.

Another object of the present invention is to provide a method for drilling and completing of offshore wells from a remote location without the aid of divers or without employing a rigid structure extending from the well to a point above the surface of the water.

Still another object of the present invention is to provide a method for re-entering, either with wire line or rotary equipment, an offshore well whose Wellhead assembly is located well below the surface of the body of water.

Another object of the present invention is to provide a method for maintaining control of an offshore well at all times during drilling, completion and production operations.

A still further object of this invention is to provide a method of running and cementing multiple strings of pipe within a well drilled at an offshore location.

It is also an object of the present invention to provide a method for connecting a Christmas tree to a well tubing at a point above the surface of the water before running the Christmas tree to its position near the ocean floor.

A further object of this invention is to provide well drilling and completion apparatus utilizing self-energizing seals.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view illustrating the 3,256,937 Patented June 21, 1966 fioatable drilling barge anchored to the ocean floor over a drilling location and supporting a wellhead support frame and container;

FIGURE 2 is a partial diagrammatic view of the equipment of FIGURE 1 with a conductor pipe extending through the wellhead container to a position close to the 'ocean floor;

FIGURE 3 is a diagrammatic view showing the equipment of FIGURE 2 with a drill string extending through the conductor pipe and starting a hole in the ocean floor;

FIGURE 4 is a diagrammatic view illustrating the withdrawal of a bit and drill string from the hole that has been drilled for the conductor pipe;

FIGURES 5 and 6 are diagrammatic views illustrating the lowering of the conductor pipe and the wellhead container and support frame to the ocean floor with a cementing string being run in FIGURE 6 while the conductor pipe is still positioned above the bottom of the hole;

FIGURE 7 is a schematic drawing illustrating the cementing of the conductor pipe in the borehole with the wellhead support frame positioned on the ocean floor;

FIGURE 8 is a schematic drawing illustrating continuation of the drilling operations through the conductor P P FIGURE 9. is a view taken in longitudinal cross-section of a casinghead supported in the wellhead container;

FIGURE 10 is a view illustrating the operation of lowering a landing head and blow-out preventer on top of the casinghead;

FIGURE 11 is a view showing the lowering of a marine conductor with its landing head about to be set down on a mandrel on the top of a blow-out preventer;

FIGURE 12 is a view of the equipment within the wellhead container while carrying out the drilling operation illustrated in FIGURE 8;

FIGURE 13 is a view taken in longitudinal crosssection of the wellhead equipment prior to carrying out a cementing operation; 7

FIGURE 14 is a view taken in longitudinal cross-section of the seal and lock hold-down head in its inoperative and operative positions;

FIGURE 15 is a schematic view of a portion of the wellhead equipment taken in longitudinal cros-section after a cementing operation is carried out;

FIGURE 16 illustrates the wellhead after blow-out preventers have been mounted thereon;

FIGURE 17 is a diagrammatic view of a production control unit being lowered to an underwater wellhead;

FIGURE 18 is a view of another form of a wellhead support structure;

FIGURE 19 is a view taken in longitudinal cross-section of an annular sealing device illustrating 'its operative and inoperative positions;

FIGURE 20 isa view taken in longitudinal cross-section of a toolfor locking equipment into place;

FIGURE 21 is an isometric view showing the tool guide assembly mounted on the wellhead container;

FIGURE 22 is a plan view of the equipment shown in FIGURE 21;

FIGURES 23 and 24 are longitudinal views of single and dual tubing strings suspended from a running tool;

FIGURE 25 is a view illustrating another apparatus for lowering the casinghead to the ocean floor;

FIGURES 26a and 261; are views taken partly in longil tion of the lower end of the wellhead assembly connected to dual tubing strings;

FIGURE 30 is a diagrammatic view illustrating an arrangement of packers and tubings within a well;

FIGURES 31 to 34 are schematic views showing installation of dual tubing strings within an underwater well casinghead; and,

FIGURE 35 is a plan assembly of FIGURE 29.

Referring to FIGURE barge 11, of any suitable floatable type is illustrated as floating on the surface of the water 12 and fixedly positioned over a preselected drilling location by being anchored to the ocean floor 13 by anchors 14 and 15. Equipment of this type may be used when carrying on well drilling operations in water varying from about 100 feet to 1,500 feet or more. The drilling barge is equipped with a suitable derrick 16 containing fall line 17 and a hoist 18 and rotary table 21 as well as other auxiliary equipment needed during the drilling of a well. The derrick 16 is positioned over a drilling slot or well 22 which extends vertically through the barge in a conventional manner. When using the equipment of the present invention the slot 22 in the barge 11 may be either centrally located or extend in from one edge. However, drilling operations may be carried out over the side of the barge without use of a slot.

A wellhead support structure, such as a container 23, which is preferably in the form of an open top tank, and its horizontally extending support frame 24 is-shown as being suspended in the well 22 of the barge 11 by means of two or more cables 25 and 26 which run to individual hoists 27 and 28, or other suitable means. This arrangement provides means for subsequently lowering the wellhead container and its support frame to the ocean floor. In some circumstances the container 23 and its support frame 24 may comprise a unitary structure of interconnected girders 199 and crossbracing members 200 as shown in FIGURE 18.

Prior to commencing drilling operations a large diameter conductor pipe 31, which may be from 2048 inches in diameter, is lowered through the bottom of the wellview of the tubing lock-down ,head container 23 and suspended therein in any suitable manner, as by slips. As shown in FIGURES 2 and 3, drilling operations commence with the conductor pipe 31 being positioned with its lower end a short distance above the ocean floor 13 to permit circulation of drilling fluid (sea water) upwardly from the hole 32 being drilled. Alternatively the hole may be drilled and the conductor pipe slipped over the drill string and down into the hole afterwards. As shown in FIGURE 3, the drilling of a borehole 32 for a 20-inch conductor pipe 31 may be ac complished by mounting a 17 /2-inch drill bit 33 at the lower end of a drill string or stem 34 with, for example,

a 24-inch collapsible under-reamer bit 35 mounted above y bit 33. An example of an under-reamer bit 35 is a Baker Model D Rotary Hydraulic Expansion Wall Scraper. The borehole 32 to accommodate the conductor 31 may be drilled from the ocean floor to a distance of from 200 to 600 feet or more below the mudline. Drilling operations are carried out while preferably circulating sea water down through the drill stem 34 without any return of the drilling fluid to the drilling barge 11, i.e., the drilling fluid is lost into the ocean. Since the drilling barge 11 is anchored in place by anchors 14 and as shown in FIGURE 1, there is little rise and fall of the drilling barge 11 on the surface of the water 12 with respect to its position above the ocean floor 13, but preferably a conventional telescoping bumper sub is employed in the drill string to allow some vertical extension of the string. Since there is the possibility of slight horizontal movement of the drilling barge on the surface of the water, at some locations it is necessary to use a conductor pipe larger than inches in diameter at the mudline to provide enough strength to resist the lateral loads, in addition to the normal vertical loads, which would result 1 of the drawing, a drilling drilling barge.

from the vessel being displaced slightly off the hole during drilling operations. Thus, a 36- or 48-inch conductor pipe or foundation pile may be necessary near the mudline. However, for purposes of illustration, the present invention will be described hereinbelow with a 24-inch diameter conductor pipe being employed that was swaged down to 20 inches.

Boring of the hole 32 for the conductor pipe has been accomplished in FIGURE 4 and the drill bits 33 and 35 are being withdrawn on the drill stem upwardly to the Just prior to withdrawing the bit from the hole 32 the conductor pipe 31 is lowered slightly into the hole 32 as it would otherwise be difiicult to stab the conductor 31 accurately into the hole 32 after the drill string and bit have been withdrawn therefrom.

In FIGURE 5 the conductor pipe 31 is shown being lowered into the borehole 32. In drilling in some formations, it is often advantageous to switch from sea water as a drilling fluid to a clay-containing drilling mud before running the 20-inch conductor pipe into the hole in order to facilitate running of the pipe and to control the hole against caving.

Prior to lowering the conductor pipe 31 and the wellhead container 23, a casinghead 36 which is fixedly secured to a base plate 37 and radial reinforcing ribs 38 is positioned in the hole in the bottom of the wellhead container 23, as shown in FIGURE 9, with the lower end of the casinghead 36a extending downwardly a distance sufficient so that the top of the conductor pipe 31 can be fixedly secured thereto in any suitable manner as by screw threads or welding. The wellhead container 23 in turn is fixedly secured to one or more girders 24a of the support frame 24 in any suitable manner as by welding. Positioned along the vertical wall of the wellhead container 23, either inside thereof, are two or more guide tubes 41 and 42 which are provided with guide line anchoring means 43a and 44a at the bottom thereof, respectively, to which the hoist lines 25 and 26, which will later be utilized as guide lines for installing other equipment, may be securely anchored.

A circumferential groove 43 is provided in at least a portion of the outer wall of the casinghead 36 (FIG. 9), preferably near the top thereof, to provide means for temporarily locking other equipment to the casinghead. Additionally, one or more internal grooves 44 and 45 are provided for seating and locking an annular seal (not shown) below a tapered shoulder 46 which is formed on the inside wall of the casinghead for seating a casing and tubing suspension body or mandrel thereon. A conduit 47 is provided through the casinghead 36 which is in communication with the interior of the casinghead below grooves 44 and 45 and with the exterior. The conduit 47 is normally closed by a remotely operated valve 48 which may be of any suitable type, either electrically, pneumatic, or hydraulically operated. For purposes of illustration, this application will be described with regard to using hydraulically-operated valves. Thus, valve 48 may be energized by hydraulic fluids entering or returning through pressure lines 51 and 52 which exin order to determine when sufficient cement has been pumped into the well. This service line 53 may be also used as a choke, fill-up or kill line.

With the wellhead container 23 suitably connected to the casinghead 36 which is in turn connected to the top of the conductor pipe 31, the entireassembly is lowered on a drill pipe running string or on hoist lines 25 and 26 by unreeling hoists 27 and 28. At the time the wellhead container is lowered, a cementing string of pipe 54 is run down through the wellhead container and into the conductor pipe 31, until its lower end is just above the bot; tom of the pipe 31, as shown in FIGURE 6.

The wellhead container and its support frame 24 are then lowered to the ocean floor 13 as shown in FIGURE 7 and cement is pumped down through a cementing string 54 and up the annular space between the conductor pipe 31 and the borehole wall 32a in a quantity sufiicient to fill the annular space causing it to overflow and form a cement pad in and around the wellhead support frame 24. The amount of cement needed is generally determined by calculating the volume of the hole to be cemented and the size of the cement pad 55 wanted at the top of the hole on the ocean floor. It is realized that instead of employing hoist cables 25 and 26 to lower the wellhead container 23 and its support frame 24, the entire apparatus may be lowered in place on the ocean floor by employing a running string 39 (FIG. 25) which is essentially a pipe string similar to the cementing string 54 of FIGURE 6 with suitable coupling means, such as a jay tool 49, attached to the lower end thereof for connecting below lugs 43a or into groove 43 of the casinghead 36 during the lowering of the assembly into position.

Prior to continuing the drilling operations through the conductor pipe 31, it is necessary to mount a conventional blow-out preventer 56 (see FIG. over the casinghead 36. The blow-out preventer 56 is of a conventional type except that it is provided with two or more guide arms 57 and 58 with guide cones 62 and 63 attached to the outer ends thereof, preferably by swivel joints to facilitate aligning. The guide cones are of a diameter slightly less than the inner diameter of the guide tubes 41 and 42 and have a lower portion that tapers downwardly, as illustrated in FIGURE 10.

As shown in FIGURES 21 and 22, the wellhead container 23 is provided at the top thereof with an upwardly and outwardly sloping flange 64 while guide tubes 40, 41 and 42 are attached to the outside of the container 23, as by welding, in order to give greater clearance within the container itself. Preferably, each of the guide tubes 40, 41 and 42 has a cone-shaped flange 65, 66 and 67 attached to its upper end which serves to align guide cones 61, 62 and 63 as they move downwardly into the guide tubes. Each of the guide cones 61, 62 and 63 is provided with a vertical hole therethrough of a diameter slightly larger than the guide cables 25, 26 and 29 thus allowing the guide cones to pass freely down the cable and rest within their respective guide tubes 40, 41- and 42. The wellhead container 23 as well as the adjacent walls of the fixedly secured guide tubes 40, 41 and 42 are provided with slots 71, 72 and 73 therein in order to enable the arms 57, 58 and 59 to pass therethrough. The slots are preferably smaller than the diameter of the guide cables to hold the cables in the tubes.

Returning to FIGURE 10 of the drawing, the blowout preventer is shown as being connected to the top of a hydraulically-operated seal and lock hold-down head 74 which is actuated by hydraulic pressure through pressure lines 75 and 76. The. seal and lock hold-down head 74 was previously flanged to the bottom of the blow-out preventer 56 on the drilling vessel after which the guide wires 25 and 26 were threaded through the guide cones 63 and 62. For purposes of clarity of description, the operation of the equipment of the present invention will be described with regard to only two of the guide lines. The combined blow-out preventer 56 and hold-down head 74 were lowered into position by means of a running string 77 which was connected to the top of the blow-out preventer 56 by means of a running or lowering head 78. It is realized that the running string, which is essentially a long string of pipe extending from the drilling vessel down to the ocean floor, may be provided at its-lower end with any suitable connecting means for connecting it to the blow-out preventer 56 or its associated movable equipment. In the particular arrangement shown the running head 78 comprises a tubular member adapted to fit over a mandrel 81 extending upwardly from the blow-out preventer 56. The mandrel 81 is provided with a pin 82 which is adapted to seat in a J-slot in the run- 7 ning head. This is a well known means of connecting elements in the field of well drilling although-it is to be realized that the threaded joint could be employed equally as well. Additionally, instead of using a running string 77 the equipment could be lowered into place by means of a wire line having a quick disconnect socket attached to its lower end.

In FIGURE 10 a seal and lock-down head 74, known as a'wellhead connector, manufactured by Hydril Co., Los Angeles, California, is illustrated just prior to lowering it into position on the casinghead 36. In FIGURE 14, the seal and lock-down head is shown in greater detail after it has been lowered into position on the casinghead 36. As shown in FIGURE 14, the seal and lock-down head comprises an annular housing 84 whose inner diameter is just slightly larger than the outer diameter of the casinghead 36. The annular housing 84 is provided with an "annular chamber 85 in which there is movably mounted an annular sleeve 86 having a tapered face or shoulder 87 on the inside thereof. The annular chamber 85 is also provided with a plurality of locking blocks or dogs 88, each of which is provided with a vertical slot 91 which is substantially wider than a pin 92 passing therethrough thus permitting movement of the dogs 88 so that they extend, in an' operative position, into the bore of the holddown head, as shown in the right-hand half of FIGURE 14-. In their inoperative position the dogs 88 normally extend into a recessed portion 93 of the annular sleeve 86, being forced to this position when the hold-down head was originally forced over the casinghead 36. By applying hydraulic pressure through pressure conduit 75, the annular sleeve 86 is forced downwardly so that its tapered shoulder 87 contacts the locking dog 88 forcing it out of the recess 93, from the position shown on the lefthand side of FIGURE 14 to the position shown in the right-hand side of FIGURE 14. At this time the holddown head 74 is fixedly locked on the casinghead 36. At the same time an annular seal 94 carried by the housing 84 forms a fluidtight seal between the hold-down head 74 and the casinghead 36.

After the blow-out preventer 56 and the hold-down head 74 of FIGURE 10 have been secured to the casinghead 36, the nlnning string 77 (FIGURE 10) is disconnected from the mandrel 81 at the top of the blow-out preventer 56 by lowering the running string slightly, rotating it counterclockwise a short distance and then lifting 7 up on it to disconnect pin 82 from the J-slot 83, in a manner well known to the art. As shown in FIGURE 11, a landing head 95 which was previously flanged to the bottom of a 22-inch marine conductor 96 on the drilling vessel is then lowered down into place over the mandrel 81 extending upwardly from the blow-out preventer 56. To lock the landing head securely on top of the blowout preventer 56, pressure is applied to port 99. The landing head is a unit known to the oil Well art as a modified Regan Forge and Engineering Co., California, type K blow-out preventer which is provided with an annular packer which cooperates with the mandrel 81 to form a fluidtight connection therewith. Since this element is well known to the art it will not be further described at this point.

As shown in FIGURE 11 the landing head 95 is provided with a pair of guide arms 97 and 98 to which a pair of guide cones 101 and 102 are attached and adapted to slide downwardly on the guide wires 25 and 26. It is realized that the 20-inch blow-out preventer could be provided as an integral part of the 20-inch casinghead 36 thus obviating this temporary connection to the casinghead by means of seal and lock-down head 74. However, this procedure would require leaving the 20-inch blowout preventer 56 in the well-head container to become part of the permanent wellhead installation.

After the equipment of FIGURE 11 has been lowered into place as shown in FIGURE '12, a drill string 34 in- 

4. A METHOD OF COMPLETING FROM A FLOATING VESSEL AN UNDERWATER WELL POSITIONED BENEATH SAID VESSEL AND HAVING GUIDE MEANS EXTENDING THEREBETWEEN AND HAVING A CASINGHEAD POSITIONED ABOVE THE OCEAN FLOOR WITH CASING EXTENDING INTO THE WELL AND CEMENTED THEREIN, SAID METHOD COMPRISING (A) POSITIONING A STRING OF TUBING IN THE WELL CASING WITH THE UPPER PORTION OF SAID TUBING STRING EXTENDING UPWARDLY TO A POINT ABOVE THE SURFACE OF A BODY OF WATER ADJACENT SAID VESSEL, (B) ATTACHING A VALVED PRODUCTION WELLHEAD ASSEMBLY TO THE TOP OF SAID TUBING STRING, (C) LOWERING THE UPPER PORTION OF SAID TUBING STRINGS INTO SAID WELL CASING WHILE GUIDING THE PRODUCTION 